To my knowledge Google Cloud Load Balancer is not supporting HTTP to HTTPS redirect out of the box and it's a known issue: https://issuetracker.google.com/issues/35904733
Currently, I'm sending certain requests to GKE backend where I run Kubernetes apps and I have GCS-backed backends. I'm also using Apache in the default backend where I force HTTPS.
Problem with this approach is that, if any request match the criteria for GKE backend, I have no way to force HTTPS. I'm thinking to use Apache backend for all requests (?) and somehow proxy some of them to GKE backend. This way Apache backend becomes a bottleneck and I'm not sure if it's a good solution at all.
How would you approach this problem? Thanks in advance!